| /* $Id: entry.S,v 1.37 2004/06/11 13:02:46 doyu Exp $ |
| * |
| * linux/arch/sh/entry.S |
| * |
| * Copyright (C) 1999, 2000, 2002 Niibe Yutaka |
| * Copyright (C) 2003 Paul Mundt |
| * |
| * This file is subject to the terms and conditions of the GNU General Public |
| * License. See the file "COPYING" in the main directory of this archive |
| * for more details. |
| * |
| */ |
| |
| ! NOTE: |
| ! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address |
| ! to be jumped is too far, but it causes illegal slot exception. |
| |
| /* |
| * entry.S contains the system-call and fault low-level handling routines. |
| * This also contains the timer-interrupt handler, as well as all interrupts |
| * and faults that can result in a task-switch. |
| * |
| * NOTE: This code handles signal-recognition, which happens every time |
| * after a timer-interrupt and after each system call. |
| * |
| * NOTE: This code uses a convention that instructions in the delay slot |
| * of a transfer-control instruction are indented by an extra space, thus: |
| * |
| * jmp @k0 ! control-transfer instruction |
| * ldc k1, ssr ! delay slot |
| * |
| * Stack layout in 'ret_from_syscall': |
| * ptrace needs to have all regs on the stack. |
| * if the order here is changed, it needs to be |
| * updated in ptrace.c and ptrace.h |
| * |
| * r0 |
| * ... |
| * r15 = stack pointer |
| * spc |
| * pr |
| * ssr |
| * gbr |
| * mach |
| * macl |
| * syscall # |
| * |
| */ |
| |
| #if defined(CONFIG_PREEMPT) |
| # define preempt_stop() cli |
| #else |
| # define preempt_stop() |
| # define resume_kernel __restore_all |
| #endif |
| |
| |
| .align 2 |
| ENTRY(exception_error) |
| ! |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 2f, r0 |
| jsr @r0 |
| nop |
| #endif |
| sti |
| mov.l 1f, r0 |
| jmp @r0 |
| nop |
| |
| .align 2 |
| 1: .long do_exception_error |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| 2: .long trace_hardirqs_on |
| #endif |
| |
| .align 2 |
| ret_from_exception: |
| preempt_stop() |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 4f, r0 |
| jsr @r0 |
| nop |
| #endif |
| ENTRY(ret_from_irq) |
| ! |
| mov #OFF_SR, r0 |
| mov.l @(r0,r15), r0 ! get status register |
| shll r0 |
| shll r0 ! kernel space? |
| get_current_thread_info r8, r0 |
| bt resume_kernel ! Yes, it's from kernel, go back soon |
| |
| #ifdef CONFIG_PREEMPT |
| bra resume_userspace |
| nop |
| ENTRY(resume_kernel) |
| mov.l @(TI_PRE_COUNT,r8), r0 ! current_thread_info->preempt_count |
| tst r0, r0 |
| bf noresched |
| need_resched: |
| mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags |
| tst #_TIF_NEED_RESCHED, r0 ! need_resched set? |
| bt noresched |
| |
| mov #OFF_SR, r0 |
| mov.l @(r0,r15), r0 ! get status register |
| and #0xf0, r0 ! interrupts off (exception path)? |
| cmp/eq #0xf0, r0 |
| bt noresched |
| |
| mov.l 1f, r0 |
| mov.l r0, @(TI_PRE_COUNT,r8) |
| |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 3f, r0 |
| jsr @r0 |
| nop |
| #endif |
| sti |
| mov.l 2f, r0 |
| jsr @r0 |
| nop |
| mov #0, r0 |
| mov.l r0, @(TI_PRE_COUNT,r8) |
| cli |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 4f, r0 |
| jsr @r0 |
| nop |
| #endif |
| |
| bra need_resched |
| nop |
| |
| noresched: |
| bra __restore_all |
| nop |
| |
| .align 2 |
| 1: .long PREEMPT_ACTIVE |
| 2: .long schedule |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| 3: .long trace_hardirqs_on |
| 4: .long trace_hardirqs_off |
| #endif |
| #endif |
| |
| ENTRY(resume_userspace) |
| ! r8: current_thread_info |
| cli |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 5f, r0 |
| jsr @r0 |
| nop |
| #endif |
| mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags |
| tst #_TIF_WORK_MASK, r0 |
| bt/s __restore_all |
| tst #_TIF_NEED_RESCHED, r0 |
| |
| .align 2 |
| work_pending: |
| ! r0: current_thread_info->flags |
| ! r8: current_thread_info |
| ! t: result of "tst #_TIF_NEED_RESCHED, r0" |
| bf/s work_resched |
| tst #(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), r0 |
| work_notifysig: |
| bt/s __restore_all |
| mov r15, r4 |
| mov r12, r5 ! set arg1(save_r0) |
| mov r0, r6 |
| mov.l 2f, r1 |
| mov.l 3f, r0 |
| jmp @r1 |
| lds r0, pr |
| work_resched: |
| #if defined(CONFIG_GUSA) && !defined(CONFIG_PREEMPT) |
| ! gUSA handling |
| mov.l @(OFF_SP,r15), r0 ! get user space stack pointer |
| mov r0, r1 |
| shll r0 |
| bf/s 1f |
| shll r0 |
| bf/s 1f |
| mov #OFF_PC, r0 |
| ! SP >= 0xc0000000 : gUSA mark |
| mov.l @(r0,r15), r2 ! get user space PC (program counter) |
| mov.l @(OFF_R0,r15), r3 ! end point |
| cmp/hs r3, r2 ! r2 >= r3? |
| bt 1f |
| add r3, r1 ! rewind point #2 |
| mov.l r1, @(r0,r15) ! reset PC to rewind point #2 |
| ! |
| 1: |
| #endif |
| mov.l 1f, r1 |
| jsr @r1 ! schedule |
| nop |
| cli |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 5f, r0 |
| jsr @r0 |
| nop |
| #endif |
| ! |
| mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags |
| tst #_TIF_WORK_MASK, r0 |
| bt __restore_all |
| bra work_pending |
| tst #_TIF_NEED_RESCHED, r0 |
| |
| .align 2 |
| 1: .long schedule |
| 2: .long do_notify_resume |
| 3: .long restore_all |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| 4: .long trace_hardirqs_on |
| 5: .long trace_hardirqs_off |
| #endif |
| |
| .align 2 |
| syscall_exit_work: |
| ! r0: current_thread_info->flags |
| ! r8: current_thread_info |
| tst #_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | _TIF_SYSCALL_AUDIT, r0 |
| bt/s work_pending |
| tst #_TIF_NEED_RESCHED, r0 |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 5f, r0 |
| jsr @r0 |
| nop |
| #endif |
| sti |
| ! XXX setup arguments... |
| mov r15, r4 |
| mov #1, r5 |
| mov.l 4f, r0 ! do_syscall_trace |
| jsr @r0 |
| nop |
| bra resume_userspace |
| nop |
| |
| .align 2 |
| syscall_trace_entry: |
| ! Yes it is traced. |
| ! XXX setup arguments... |
| mov r15, r4 |
| mov #0, r5 |
| mov.l 4f, r11 ! Call do_syscall_trace which notifies |
| jsr @r11 ! superior (will chomp R[0-7]) |
| nop |
| ! Reload R0-R4 from kernel stack, where the |
| ! parent may have modified them using |
| ! ptrace(POKEUSR). (Note that R0-R2 are |
| ! used by the system call handler directly |
| ! from the kernel stack anyway, so don't need |
| ! to be reloaded here.) This allows the parent |
| ! to rewrite system calls and args on the fly. |
| mov.l @(OFF_R4,r15), r4 ! arg0 |
| mov.l @(OFF_R5,r15), r5 |
| mov.l @(OFF_R6,r15), r6 |
| mov.l @(OFF_R7,r15), r7 ! arg3 |
| mov.l @(OFF_R3,r15), r3 ! syscall_nr |
| ! |
| mov.l 2f, r10 ! Number of syscalls |
| cmp/hs r10, r3 |
| bf syscall_call |
| mov #-ENOSYS, r0 |
| bra syscall_exit |
| mov.l r0, @(OFF_R0,r15) ! Return value |
| |
| __restore_all: |
| mov.l 1f, r0 |
| jmp @r0 |
| nop |
| |
| .align 2 |
| 1: .long restore_all |
| |
| .align 2 |
| syscall_badsys: ! Bad syscall number |
| mov #-ENOSYS, r0 |
| bra resume_userspace |
| mov.l r0, @(OFF_R0,r15) ! Return value |
| |
| /* |
| * The main debug trap handler. |
| * |
| * r8=TRA (not the trap number!) |
| * |
| * Note: This assumes that the trapa value is left in its original |
| * form (without the shlr2 shift) so the calculation for the jump |
| * call table offset remains a simple in place mask. |
| */ |
| debug_trap: |
| mov r8, r0 |
| and #(0xf << 2), r0 |
| mov.l 1f, r8 |
| add r0, r8 |
| mov.l @r8, r8 |
| jmp @r8 |
| nop |
| |
| .align 2 |
| 1: .long debug_trap_table |
| |
| /* |
| * Syscall interface: |
| * |
| * Syscall #: R3 |
| * Arguments #0 to #3: R4--R7 |
| * Arguments #4 to #6: R0, R1, R2 |
| * TRA: (number of arguments + ABI revision) x 4 |
| * |
| * This code also handles delegating other traps to the BIOS/gdb stub |
| * according to: |
| * |
| * Trap number |
| * (TRA>>2) Purpose |
| * -------- ------- |
| * 0x00-0x0f original SH-3/4 syscall ABI (not in general use). |
| * 0x10-0x1f general SH-3/4 syscall ABI. |
| * 0x20-0x2f syscall ABI for SH-2 parts. |
| * 0x30-0x3f debug traps used by the kernel. |
| * 0x40-0xff Not supported by all parts, so left unhandled. |
| * |
| * Note: When we're first called, the TRA value must be shifted |
| * right 2 bits in order to get the value that was used as the "trapa" |
| * argument. |
| */ |
| |
| .align 2 |
| .globl ret_from_fork |
| ret_from_fork: |
| mov.l 1f, r8 |
| jsr @r8 |
| mov r0, r4 |
| bra syscall_exit |
| nop |
| .align 2 |
| 1: .long schedule_tail |
| |
| /* |
| * The poorly named main trapa decode and dispatch routine, for |
| * system calls and debug traps through their respective jump tables. |
| */ |
| ENTRY(system_call) |
| #if !defined(CONFIG_CPU_SH2) |
| mov.l 1f, r9 |
| mov.l @r9, r8 ! Read from TRA (Trap Address) Register |
| #endif |
| /* |
| * Check the trap type |
| */ |
| mov #((0x20 << 2) - 1), r9 |
| cmp/hi r9, r8 |
| bt/s debug_trap ! it's a debug trap.. |
| mov #OFF_TRA, r9 |
| add r15, r9 |
| mov.l r8, @r9 ! set TRA value to tra |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 5f, r10 |
| jsr @r10 |
| nop |
| #endif |
| sti |
| |
| ! |
| get_current_thread_info r8, r10 |
| mov.l @(TI_FLAGS,r8), r8 |
| mov #(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT), r10 |
| tst r10, r8 |
| bf syscall_trace_entry |
| ! |
| mov.l 2f, r8 ! Number of syscalls |
| cmp/hs r8, r3 |
| bt syscall_badsys |
| ! |
| syscall_call: |
| shll2 r3 ! x4 |
| mov.l 3f, r8 ! Load the address of sys_call_table |
| add r8, r3 |
| mov.l @r3, r8 |
| jsr @r8 ! jump to specific syscall handler |
| nop |
| mov.l @(OFF_R0,r15), r12 ! save r0 |
| mov.l r0, @(OFF_R0,r15) ! save the return value |
| ! |
| syscall_exit: |
| cli |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| mov.l 6f, r0 |
| jsr @r0 |
| nop |
| #endif |
| ! |
| get_current_thread_info r8, r0 |
| mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags |
| tst #_TIF_ALLWORK_MASK, r0 |
| bf syscall_exit_work |
| bra __restore_all |
| nop |
| .align 2 |
| #if !defined(CONFIG_CPU_SH2) |
| 1: .long TRA |
| #endif |
| 2: .long NR_syscalls |
| 3: .long sys_call_table |
| 4: .long do_syscall_trace |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| 5: .long trace_hardirqs_on |
| 6: .long trace_hardirqs_off |
| #endif |
